diff --git a/app/src/main/java/io/legado/app/ui/book/read/ReadBookBaseActivity.kt b/app/src/main/java/io/legado/app/ui/book/read/ReadBookBaseActivity.kt
index 582a3c793..71d2b760c 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/ReadBookBaseActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/ReadBookBaseActivity.kt
@@ -157,17 +157,17 @@ abstract class ReadBookBaseActivity :
                         0
                     }
                 when (navigationBarPos) {
-                    0 -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
+                    POS.BOTTOM -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
                         height = navigationBarHeight
                         width = MATCH_PARENT
                         gravity = Gravity.BOTTOM
                     }
-                    1 -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
+                    POS.LEFT -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
                         height = MATCH_PARENT
                         width = navigationBarHeight
                         gravity = Gravity.LEFT
                     }
-                    2 -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
+                    POS.RIGHT -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
                         height = MATCH_PARENT
                         width = navigationBarHeight
                         gravity = Gravity.RIGHT
diff --git a/app/src/main/java/io/legado/app/ui/book/read/ReadMenu.kt b/app/src/main/java/io/legado/app/ui/book/read/ReadMenu.kt
index bf37f1134..a4c5de847 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/ReadMenu.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/ReadMenu.kt
@@ -316,9 +316,9 @@ class ReadMenu @JvmOverloads constructor(
                     vwMenuBg.setOnClickListener { runMenuOut() }
                     root.padding = 0
                     when (activity?.navigationBarPos) {
-                        0 -> root.bottomPadding = navigationBarHeight
-                        1 -> root.leftPadding = navigationBarHeight
-                        2 -> root.rightPadding = navigationBarHeight
+                        POS.BOTTOM -> root.bottomPadding = navigationBarHeight
+                        POS.LEFT -> root.leftPadding = navigationBarHeight
+                        POS.RIGHT -> root.rightPadding = navigationBarHeight
                     }
                 }
                 if (!LocalConfig.readMenuHelpVersionIsLast) {
diff --git a/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt b/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt
index 77dc417bf..3163fcf98 100644
--- a/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt
+++ b/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt
@@ -77,24 +77,22 @@ val Activity.navigationBarHeight: Int
  * 1 left
  * 2 right
  */
-val Activity.navigationBarPos: Int
+val Activity.navigationBarPos: POS
     get() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
-            var pos = 0
             val display: Display = windowManager.defaultDisplay
             val rotate: Int = display.rotation
             val height: Int = display.height
             val width: Int = display.width
-            pos = if (width > height) {
+            return if (width > height) {
                 if (rotate == Surface.ROTATION_270) {
-                    1 //left
+                    POS.LEFT
                 } else {
-                    2 //right
+                    POS.RIGHT
                 }
             } else {
-                0 //bottom
+                POS.BOTTOM
             }
-            return pos
         } else {
             val display: Display = windowManager.defaultDisplay
             val metricsReal = DisplayMetrics()
@@ -110,9 +108,13 @@ val Activity.navigationBarPos: Int
             val realH = metricsReal.heightPixels
 
             return if (currW != realW && currH == realH) {
-                2
+                POS.RIGHT
             } else {
-                0
+                POS.BOTTOM
             }
         }
-    }
\ No newline at end of file
+    }
+
+enum class POS {
+    BOTTOM, LEFT, RIGHT
+}
\ No newline at end of file